Announcing Windows Server 2019 Insider Preview Build 17666

Today we are pleased to release a new build of the Windows Server vNext Long-Term Servicing Channel (LTSC) release that contains both the Desktop Experience as well as Server Core in all 18 server languages, as well as a new build of the next Windows Server Semi-Annual Channel release.

There are two major areas that we would like you to try out in each preview release and report back any issues:

Application compatibility – please let us know if any server roles or applications stops working or fails to function as it used to

What’s New in the Latest Build

Click here to see the full list of new features introduced in earlier builds.

Performance history for Storage Spaces Direct

This build improves the Get-ClusterPerformanceHistory cmdlet to be more scripting-friendly. It’s now convenient to pipe performance history into utility cmdlets like Sort-Object, Where-Object, and Measure-Object so you can quickly find the average or peak value, filter values, plot trend lines, run outlier detection, and more. You can see examples with these cmdlets in the topics linked under “Insider Preview content” on aka.ms/StorageSpacesDirect.

This build adds performance history for the Storage Spaces Direct cache for reads (% hit rate) and writes (% full), as well as the CSV in-memory read cache (% hit rate). These new series are available per-server and in aggregate.

Some performance history series have changed names in this build for greater clarity and consistency—for example, Node.Cpu.Usage is now ClusterNode.Cpu.Usage. Note that this change will result in some blank charts in Windows Admin Center until its next update.

Delimit volume allocation with Storage Spaces Direct

New cmdlets, provided in this build, simplify the management of volumes with delimited allocation. Use Get-StorageScaleUnit to see fault domains; follow associations to/from Get-VirtualDisk to see the current allocation; and set or modify allocation by using friendly names for fault domains. For more details, see the links under “Insider Preview content” on aka.ms/StorageSpacesDirect.

Available Content

Windows Server 2019 Preview is available in ISO format in 18 languages, and in VHDX format in English only. This build and all future pre-release builds will require the use of activation keys during setup. The following keys allow for unlimited activations:

Use your registered Windows 10 Insider device and use the Feedback Hub application. In the app, choose the Server category and then the appropriate subcategory for your feedback. Please indicate what build number you are providing feedback on. We also encourage you to visit the Windows Server Insiders space on the Microsoft Tech Communities forum to collaborate, share and learn from experts.

Known Issues

The size of a file according to NTFS and a stream control block can become different from the size according to Cache Manager. This might cause a bug check if a read operation is out of bounds for the file size that Cache Manager has stored.

Editing or creating policies for AppLocker can cause the MMC snap-in to crash when generated rules for a packaged app.

After upgrading the operating system, the AppX database may have corrupted entries, which causes problems for components that use those entries.

Terms of Use

This is pre-release software – it is provided for use “as-is” and is not supported in production environments. Users are responsible for installing any updates made available from Windows Update for as long as this build is available All pre-release software made available to you via the Windows Server Insider Program are governed by the Insider Terms of Use, which takes precedence over any license agreement that may be in the product.